Studies on the properties of pneumococcal and Pseudomonas aeruginosa cytolytic toxins will be extended to include the effects of these agents on polymorphonuclear leucocytes - specifically on viability, integrity, and lysosomal enzyme release. The effects on such toxin-leucocyte interactions of various agent known to affect toxin activity or leucocyte response will also be assessed. Possible positive and negative effects of these toxins and other bacterial products on PMN chemotaxis will be examined.